PERFORMANCE BASED NAVIGATION

PBN
 PBN EVOLUTION

➢ Air Traffic Management has been one of the key areas of focus for continual
improvement in order to enhance safety and improve operational and environmental
efficiency for the regulatory authorities. The conventional navigation system uses
ground-based navigation aids to transmit signals to aircraft receivers which tie air
routes to ground-based navigation aids, making the flight path not only fixed but
also operationally inflexible.

➢ PBN is designed to provide greater flexibility and to facilitate more dynamic air
traffic management

PBN Evolution
 PBN CONCEPT
➢ The concept of PBN relies on the use of an Area Navigation (RNAV) system
combined with Required Navigation Performance (RNP)

PBN Concept
 PBN CONCEPT
➢ RNAV: Area Navigation (RNAV) enables aircraft to fly on any desired flight path
within the coverage of ground- or space-based navigation aids, within the limits of
the capability of the self-contained systems, or a combination of both capabilities.

➢ RNP: Required Navigation Performance is RNAV with the addition of an onboard

performance monitoring and alerting capability. A defining characteristic of RNP
operations is the ability of the aircraft navigation system to monitor the navigation
performance it achieves and inform the crew if the requirement is not met during an
operation.

PBN Concept
 PBN ADVANTAGES
➢ Reduces the need to maintain sensor-specific routes and procedures, and their
associated costs

➢ Avoids the need for developing sensor-specific operations with each new evolution
of navigation systems, which would be cost-prohibitive

➢ Allows for more efficient use of airspace (route placement, fuel efficiency and noise
abatement)

➢ Facilitates the operational

approval process for operator by
providing a limited set of
navigation specifications intended
for global use

PBN PBN Advantages

 ICAO PBN Manual DOC 9613

➢ Volume 1: Concept and Implementation guidance

➢ Volume 2: RVAN and RNP implementation

PBN Doc 9613

 NAVIGATION SPECIFICATION FOR EVERY FLIGHT PHASE
➢ The table below shows an overview of the navigation specifications included in
ICAO’s PBN Manual 9613. The numbers reported refer to the lateral total system
error (TSE) and longitudinal TSE that should be complied during the 95% of the
flight Arrival

PBN Navigation Specification

NAVIGATION SPECIFICATION FOR EVERY FLIGHT PHASE

PBN Navigation Specification

 REQUIRED NAVIGATION SPECIFICATION - TSE
➢ The accuracy requirement defines the 95% Total System Error (TSE) for those
dimensions where an accuracy requirement is specified.

➢ Total system error (TSE) is the difference between the true position and the desired
position.

PBN Navigation Specification - TSE

 PERFORMANCE REQUIREMENTS

➢ The requirements for PBN operations are expresed in terms of

ACCURACY

INTEGRITY

CONTINUITY

AVAILABILITY

PBN Navigation Specification

 PERFORMANCE REQUIREMENTS

➢ ACCURACY: It is the difference between the estimated position of an aircraft and

the true position. It is normally presentes as a measure of the system error.

Defined path vs desired path (NAV

Database error)
Auto Pilot’s ability to follow the
defined path

Estimated position vs actual position

➢ INTEGRITY: The ability of a system to

provide timely warning to users when the
system should not be used for navigation

PBN Navigation Specification

 PERFORMANCE REQUIREMENTS
➢ CONTINUITY: The capability of the system to perform its function without
nonscheduled interruptions during the intended operation

➢ AVAILABILITY: An indication of the ability of the system to provide usable service

within the specified coverage area and time

PBN Navigation Specification

 RAIM PREDICTION
➢ RAIM (Receiver Autonomous Integrity Monitoring): is a technology developed to
assess the integrity of a GPS receiver system

➢ RAIM is considered available if 24 GPS satellites or more are operative. If the

number of GPS satellites is 23 or fewer, RAIM availability must be checked using
approved ground-based prediction software (e.g. AUGUR-Eurocontrol)

PBN RAIM
 RAIM AVAILABILITY
➢ For those GNSS systems relying on RAIM, its availability 15 min before Estimated
Time of Arrival (ETA) until 15 min after ETA should be verified during the preflight
planning

➢ In the event of a predicted continuous loss of fault detection of more than five (5)
minutes, the flight planning should be revised (e.g. delaying the departure or
planning a different approach procedure)

➢ GPS RAIM NOTAM should be

checked on the preflight planning,
checking the unavailability period
for RNP APCH to LNAV and LNAV/
VNAV minima

PBN RAIM
 ICAO TYPES OF APPROACHES

2D approaches 3D approaches

PBN ICAO APPROACHES

 RNP NON PRECISION APPROACHES

ABAS SBAS ABAS / SBAS SBAS GNSS System

PBN RNP NPA

PRECISION APPROACHES (Non PBN)

GBAS antenna

GBAS

PBN PA
 APPROACHES COMPARATIVE

PBN Approaches Comparative

 ABAS – Aircraft Based Augmentation System

➢ An ABAS is basically a system that augments and integrates the information

obtained from the GNSS elements with information available on board the aircraft.

PBN ABAS
 SBAS – Satellite Based Augmentation System

➢ System implemented in in several regions that improves the accuracy, reliability and
integrity of the GPS signal. The SBAS vertically guided approach procedures are
considered LPV (Localizer Performance with Vertical guidance) and provide ILS
(Instrument Landing System) equivalent approach minimums as low as 200 feet at
qualifying airports.

PBN SBAS
 SBAS – Satellite Based Augmentation System

➢ The ground infrastructure includes the accurately-surveyed sensor stations which

receive the data from the primary GNSS satellites and a Processing Facility Center
which computes integrity and corrections

EGNOS Reference Station

PBN SBAS
 GBAS – Ground Based Augmentation System
➢ The GBAS provide GNSS integrity monitoring through data obtained from the
ground. A ground station at the airport transmits locally-relevant corrections,
integrity data and approach data to aircraft. GPS signals are analyzed and
corrections are sent to the aircraft via VHF Datalink

➢ GBAS, will increasingly

support CAT II/III operations
where economically
beneficial once enhanced
GNSS become available. It is
assumed that all GBAS
stations for CAT I operations
will be upgraded to CATII/III
operations

PBN GBAS
GNSS – Global Navigation Satellite System

PBN GNSS
 PBN OPERATIONS
➢ RNAV and RNP operations include certain requirements:

• Indication of aircraft position relating track

• Distance and bearing to the waypoint

• Ground Speed or time to the waypoint

• Navigation data storage function

• Failures indication of the RNAV or RNP systems

PBN PBN Operations

 PBN OPERATIONS
➢ DATABASES: The RVAN or RNP system is expected to access a navigation
database which contaings pre-stored information on NAVAID locations, waypoints,
ATS routes and Terminal procedures

➢ Commercial operators need to have documented procedures for the management

of navigations databases. Procedures will be stablished to install the databases so
that they remain current with the AIRAC cycle

➢ Remember that pilots are not allowed to use waypoints self-created. Use only the
database waypoints. The pilot is allowed to modify the speed and altitude
constraints over the waypoints

PBN PBN Operations

 RAIM AVAILABILITY

➢ During the pre-flight planning phase the availability of GPS integrity (RAIM) should
be confirmed by the crew for the intended flight (route and time).

➢ RAIM ensures that the available satellite geometry allows the receiver to calculate a
position within a specified RAIM protection limit (2.0 nm for enroute, 1.0 nm for
terminal, and 0.3 nm for non Precision approaches).

➢ During oceanic, enroute, and terminal phases of flight, RAIM is available nearly
100% of the time. The RAIM prediction function also indicates whether RAIM is
available at a specified date and time. Because of the tighter protection limit on
approaches, there may be times when RAIM is not available, that’s why RAIM
computations coverage must be checked within ±15 min of the specified departure
and arrival date and time.

➢ If RAIM is not predicted to be available for the final approach course, the approach
does not become active. If RAIM is not available when crossing the FAF, the missed
approach procedure must be flown.

PBN RAIM
 FLIGHT PLANNING
➢ where a RNAV approach is to be flown in conditions where a visual approach will
not be possible; pilots should always ensure that either:

• A different type of approach system is available at the destination, not

dependent on GPS data and for which the weather is forecast to be suitable
to enable a landing to be made from that approach, or;

• There is at least one alternate destination within range, where a different type
of approach system is available, which is not dependent on GPS data and for
which the weather is forecast to be suitable to enable a landing to be made
from that approach.

PBN FLIGHT PLANNING

 BEFORE FLYING A PBN PROCEDURE

➢ At system initialisation, the flight crew must confirm that the navigation database is
current and verify that the aircraft position has been entered correctly.

➢ The active flight plan should be checked by comparing the charts, SID or other
applicable documents, with the map display.

PBN PBN PREPARATION

 BEFORE FLYING A PBN PROCEDURE

➢ The procedure check takes into account the confirmation of the waypoint
sequence, reasonableness of track angles and distances, any altitude or speed
constraints, and, where possible, which waypoints are fly-by and which are fly-over.

➢ A procedure shall not be used if doubt exists as to the validity of the procedure in
the navigation database

➢ If the GPS receiver cannot be used for primary guidance, the appropriate
navigation receiver must be used for the selected approach (e.g., VOR or ILS).

PBN PBN PREPARATION

 FLIGHT PLAN

➢ The most relevant PBN descriptors on block 18 on the Flight Plan are:

PBN Flight Plan

 APPROACH MONITORING - LATERAL
➢ Cross-Track error is normally limited to ½ of the scale, so a Missed Approach
should be executed

➢ If the error is grater than 1 x RNP (0,3 Nm) you must execute a Missed Approach
(Inficated with a Full Scale Deflection)

PBN Approach monitoring

 APPROACH MONITORING - VERTICAL

➢ Deviation up to +/- 75 ft are acceptable

➢ This deviation could vary depending on the onboard system (verify how this
deviation is displayed)

PBN Approach monitoring

 DISCONTINUING THE APPROACH
➢ If RAIM is lost after passing the FAF the equipment should continue to provide
navigation, where possible for five minutes, before giving a RAIM loss indication
and this should be enough to complete the approach.

➢ Should RAIM detect an out of tolerance situation, a warning will be given and a
missed approach should be initiated immediately the approach should always be
discontinued:

• If the receiver fails to engage the correct approach mode or

• In case of Loss Of Integrity (LOI) monitoring or;

• Whenever the HSI/CDI indication (or GP indication where applicable) exceeds

half scale displacement or;

• If a RAIM (or equivalent) warning is activated or;

• If RAIM (or equivalent) function is not available and annunciated before

passing the FAF

PBN Discontinuing the approach

 RNP REVERSIONS
➢ For RNP approaches, some systems allow reversions if the vertical signal is lost or
degraded.

➢ If LPV to LNAV reversion takes place before the FAF/FAP, the crew can envisage
continuing with the approach to the LNAV minima.

➢ If reversion occurs after the FAF/FAP, go-around is required, unless the pilot has in
sight the visual references required to continue the approach.

PBN RNP Reversions

 TEMPERATURE CORRECTION

➢ RNP approaches with vertical guidance are allowed to be performed not below or
above a published value. Out of this value the approach is not authorised

➢ You can revert to an LNAV approach using corrections for temperature deviation
from the ISA (4% of your altitude for every 10 ºC deviation)

➢ Flying the Baro referenced RNP approaches you have to apply these corrections for
all the phases of the approach, except for the Final approach phase when the
charts is taking the temperature deviation into account

PBN Temperature Correction